Oven exhaust structure



June 14, 1966 L. J. JENN ETAL OVEN EXHAUST STRUCTURE Original Filed Feb. 26, 1962 Fig. 3.

m M m s 5 I w? Z WNW E H J, VET MA NJR 8 [J0 0m. T m LE M w W I z I n. o A 1 3 7 i F r? 3,255,746 OVEN EXHAUST STRUCTURE Louis J. Jenn and Ellsworth W. Simrns, iindianapolis, Ind.,

assignors to Jenn-Air Products Company, Inc., lndianapolis, Ind., a corporation of Indiana Original application Feb. 26, 1962, Ser. No. 175,398. Divided and this application June 11, 1965, Ser. No.

4 Claims. c1. 126-41) ovens, the fumes, heat and smoke generated in the oven during use are vented through openings in the oven door or the stove front into the room in which the oven is located. Wall-mounted domestic ovens having fume exhausting features are not unknown in the prior art, an example being the disclosure of Weaver et a1. Patent 2,836,114. The present construction distinguishes from the prior art arrangements in that, among other things, the exhaust plenum and exhaust blower and motor are mounted within a unitary oven structure. The oven and fume removal system are thus integral.

Certain safety inspection agencies, such as Underwriters Laboratories, require that before approval can be obtained, the blower unit of wall-mounted, power exhausted ovens be easily removable for cleaning. Since periodic removal of the blower unit is thus required, it is obviously desirable that mounting and location of the blower within the oven structure be such as to permit blower removal with a minimum of disassembly of the oven structure itself or demounting of the oven. In oven structures of the type referred to this is accomplished by hinging a front frame at the lower, front edge or base of the oven. The from frame may be pivoted outwardly on its hinges through a limited arc to provide access to a removable deck plate upon which the blower and its driving motor are mounted. The deck plate is shaped and mounted so that it, and consequently the blower and motor mounted thereon, can be removed and reinserted through'the access space provided by outward tilting of the front frame. The removal of the blower and its reinsertion after cleaning is thus relatively simple and requires only a minimum of manipulation or displacement of the oven structure components from their normal positions.

The removable deck plate referred to above forms the top wall of a plenum receiving the fumes prior to their entry into the blower inlet. This deck is spaced somewhat above a bottom plenum wall which overlies the upper surface of the top wall of the oven proper. Requirements of safety inspection agencies, such as Underwriters Laboratories, are stringen tin their requirement that upon shutdown, through failure or otherwise, of the blower, the heating unit of the oven must be almost immediately shut off to prevent a possibly dangerous temperature rise which would inherently occur if the oven were to remain on with the blower inoperative. This requirement has created a problem in providing a limit control response which is sensitive enough to immediately shut down the oven should the blower fail but which will not cycle the oven heating means during normal operation even during prolonged on-periods of ,the oven heating means. The concept of the present invention is the solution of this problem by adapting the sensing element of the limit control so that in normal operation it is swept by relatively cool air moving to the blower intake plenum,

but on halting of the blower, by malfunction or other- United States Patent frame.

ice

wise, the sensing element is immediately swept by relatively hot air moving to it by convection.

This concept of the present invention is specifically carried out by providing an aperture or bleed opening in the deck, the aperture registering with a conventional temperature sensing limit control mounted on a control housing carried by a front panel supported on the front With the front frame, and consequently the control housing in place, the limit control sensing element closely overlies the deck aperture. A small clearance therebetween exists, however, and this permits relatively cool air from outside the plenum (that is, from above the deck plate) to be drawn past the sensing element, through the deck aperture, and into the plenum to the fan inlet whenever the blower is operating. During normal operation, when the blower is functioning, the sensing element of the limit control is thus cooled by this air bath. This leakage or by-pass cooling air is not quantitatively large enough to appreciably affect the flow of fumes from the oven into the intake plenum induced by the blower. Should the blower fail to operate, oven-heated air in the blower intake plenum will move, by convection, through the deck aperture and will sweep past the sensing element of the limit control rapidly raising its temperature to cause it to shut down the oven heating means. A rapid temperature rise of the sensing element is thus induced upon failure of the blower to operate. The electrical controls, wiring, and blower motor, all located above the deck plate are thus protected against overheating by this rapid response of the limit control.

The object of the present invention is to provide a structure of the type described wherein the sensing element of a temperature responsive high-limit control is located so as to respond rapidly to abnormal temperature rise in the control compartment located above the plenum.

The full nature of the invention will be understood from the accompanying drawings and the following description and the claims.

FIG. 1 is a front view, installed, of an oven of the type referred to in the specification.

FIG. 2 is an enlarged, perspective view of the top portion of the oven of FIG. 1 prior to its installation in a wall opening.

FIG. 3 is an enlarged fragmentary view illustarting the placement of the limit control sensing element and the cooperating deck aperture, the arrows indicating the convection flow of hot air when the blower is inoperative.

FIG. 4 is a perspective view of the oven of FIG. 1 illustrating removal of the blower.

FIG. 5 is a fragmentary, cross-sectional view taken through the blower intake passage and illustrating the relationship of the plenum chamber thereto.

Referring initially to FIG. 1, a wall mounted oven structure ofthe type serving as environment for the present invention is shown installed or mounted within the wall 10. When installed, the visible portions of the oven include the generally rectangular frame 11 which mounts a control panel 12 within the upper marginal area enclosed by the frame. An oven door 13 is hinged in conventional fashion adjacent its lower margin to the oven structure proper. The oven structure shown in FIG. 1 also includes a lower oven door 14 also conventionally mounted by means of hinges (not shown) upon the oven structure. It will be understood that the lower oven, closed by the oven door 14, may or may not be included in the structure and the inventive features herein described can be incorporated in a single oven structure wherein the frame 11 is shorter in height so as to enclose only the oven door 13 and the control panel 12.

The interior of the oven structure illustrating the integral fume and odor control or removal system, the re-' movability of the blower unit for cleaning or repair and the arrangement for providing limit control response guarding the controls from abnormal temperature rise will now be described with particular reference to FIGS. 24. Referring particularly to FIG. 4, it will be noted that the interior of the housing accommodates an insulated oven enclosure 27 having the conventional oven racks 28 therein, the oven enclosure 27 being positioned within the housing so as to register with the oven door 13 (FIG. 1), the door having been removed from the illustration of FIG. 4 to better illustrate the interior con struction. Adjacent its upper end the housing is divided by two horizontal space plates indicated generally at 29 and 31. The space between the plates 29 and 31 provides a plenum chamber 32.

As may best be seen in FIG. 2, in which the top wall 16 of the housing has been removed, the upper face of the top plate 31 supports a 90 elbow fitting 33, one end 34 of which extends to the margin of the exhaust aperture 26 in the top wall 16 (FIG. 4). The fitting 33 is provided with generally rectangular plates whose upper margins act as supporting members for the central portion of the top wall 16 (not shown in FIG. 2). The opposite end 36 of the fitting 33 registers with the outlet passage of an electrically powered blower unit which is indicated generally at 37, the electric motor powering the blower being shown at 39.

The blower is mounted by means of a bracket 38 (FIG. 2) which is supported on the front portion of the top plate 31. A housing or duct 40 (FIG. 4) which is triangular in profile communicates with the inlet passage of the blower unit and overlies an aperture 50 in the portion 41 of the top plate 31 providing communication between the plenum chamber 32, located between the plates 29 and 31, and the blower inlet passage. It will be understood that with the blower unit in operation a negative pressure is created in the plenum chamber 32 and the air drawn therefrom is moved by the blower unit through the exhaust aperture 26 to an exhaust flue, not shown.

As previously mentioned, safety considerations require that the blower unit be removable from the oven structure for periodic cleaning and it is, of course, necessary that this removal of the blower unit be accomplished with a minimum of disassembly or dismounting of the oven structure. To permit this removal, as will subsequently be described, the top plate 31 is composed of two sections so that a front portion 41 is separable from the rear portion of the top plate. As shown in FIG. 4 the removable .front portion or deck plate 41 rests upon the upper surface of brackets 41a extending along the inner faces of the two opposite side walls 17. As will be evident from FIG. 4 the deck plate 41 has a wedge shaped inner end 42 to facilitate its removal from the open structure as will subsequently be described.

The upper marginal area of the frame accommodates the control panel 12 and supports a housing 43'(FIG. 4) which accommodates the conventional oven heat and timing control for the electrical oven heating units (not shown). As will be evident from a comparison of FIGS. 1 and 4 the upper margin of the oven door 13 is spaced from the lower margin of the control panel when the oven door is closed thereby providing a fume and odor intake slot 44 (FIG. 1) which registers with and communicates with the plenum chamber 32 (FIG. 4). A member 46 (FIG. 1) extends transversely across the frame adjacent the lower margin of the control panel 12 and is provided with a lip portion 47 (FIG. 4) which extends outwardly from the plane of the frame and serves to direct the flow of fumes and heated air through the intake slot 44.

Thus with the oven installed as indicated in FIG. 1, and with the heating controls properly set the contents of the oven will be raised to the desired temperature. During and subsequent to this temperature rise the air within the oven will be heated and will expand causing a convection current drawing fumes and odors from the oven along the upper margin of the oven door, through the intake slot 44, into the plenum chamber 32. The fumes and odors, propelled by the blower unit 37, will be exhausted through the exhaust aperture 26 to an exhaust flue. Heated air, fumes and odors will thus be moved by convection from the oven through the slight clearance which normally exists between the oven door and the front margin of the oven enclosure 27, to be subsequently drawn through the intake slot and into the plenum chamber by the blower unit.

The lip portion 47 serves its primary function when open door broiling is desired. Under these conditions the oven door is cracked open slightly, that is, placed slightly ajar so that convection currents may freely move into negative pressure area at the intake slot and the plenum chamber, this being desirable since in broiling only radiated heat from the upper oven heating units is utilized to cook the oven contents. The presence of the lip portion 47 insures that all of the fumes and odors leaving the oven when the door is ajar will be drawn into the intake slot and the plenum chamber.

To accomplish the required periodic removal of the blower unit for cleaning with a minimum amount of disassembly or dismounting of the oven structure, access space for removal of the deck plate 41 and, consequently, blower unit 37 must be provided. To provide the necessary access space, the frame 11 is supported on the front of the oven housing by means of hinges 51 (FIG. 1

- When the blower unit is to be removed, fasteners (not shown) are removed and the frame structure is pivoted forwardly away from the oven housing as illustrated in FIGS. 2 and 4. The amount of such forward pivotal movement of the frame is limited by means of the limit rods 54 (FIG. 4) which cooperate with brackets 56 to establish limits to the pivotal motion of the frame. With the frame 11 pivoted forwardly as illustrated in FIG. 2, the electrical connecting plug 57 for the blower unit motor 39 may be unplugged from its receptacle 58 carried by the control housing 43. With the oven door removed from its hinges the deck plate 41 and the broiler unit 38 mounted thereon may then be withdrawn through the oven door opening as illustrated in FIG. 4. After cleaning or maintenance has been performed on the blower unit 38 the deck plate 41 may be reinserted into the oven structure, the electrical plug 57 again connected to its receptacle 58, and the frame 11 pivoted to its operating position illustrated in FIG. 1.

Referring now to FIGS. 2 and 3, the placement of the limit control for guarding against abnormal temperature rise will now be described. It will be noted in FIG. 2 that the deck plate 41 is provided with an aperture 61 which extends therethrough and communicates with the plenum chamber 32 lying just beneath the deck plate. As may best be seen in FIG. 3 the control housing 43 supported on the frame 11 carries on its underface the temperature sensing portion 62 of a conventional temperature responsive limit control. The limit control may be of the conventional snap bimetal operated type, the temperature responsive bimetal portion 62 registering closely with the aperture 61 in'the deck plate when the frame is in its closed or operating position. When the control housing 43 is in the position shown in FIG. 3, that is, its normal operating position, there is a slight clearance between the temperature responsive element 62 and the margins of the aperture 61 permitting a circulation by convection of heated air from the plenum chamber about the temperature responsive element when the blower ceases operation, the arrows of FIG. 3 indicating this circulation. During normal operation of the blower, the plenum chamber 32 being under negative pressure, air is pulled from the cooler chamber above the plate 41 and this fiow provides a means for keeping the temperature responsive element relatively cool when the blower is operating. With the blower off and no air being drawn from above the temperature responsive element, the element will become quickly heated, because of the convection flow previously referred to, and will cut oil the oven heating elements. Since the temperature sensing element is kept relatively cool during normal operation because of its location with relation to the plenum chamber, the limit control does not cycle the oven heating elements and their operation is left to the conventional oven thermostat. Should there be an abnormal temperature rise within the plenum chamber 32 the limit control will immediately respond to shut off the oven heating elements. Should the blower unit 37 fail to operate, the heat rise in the plenum chamber necessary to cause the limit control to function will be completed relatively quickly and the heating units will be de-energized. The arrangement thus permits the oven controls including the limit control to be located above the upper plate 31 (of which the deck plate 41 is a movable section) away from the plenum chamber with the temperature responsive portion 62 of the limit control yet located in an area where it can respond rapidly, as required by safety codes, to any abnormal temperature rise in the plenum chamber. The placement of the temperature sensing portion 62 of the limit control with relation to the aperture 61 in the deck plate 41 permits the control elements themselves to be located in the relatively isolated area above the plenum chamber without atfecting the sensitivity or response of the limit control.

While the invention has been disclosed and described in some detail in the drawings and foregoing description, they are to be considered as illustrative and not restrictive in character, as other modifications may readily suggest themselves to persons skilled in this art and within the broad scope of the invention, reference being had to the appended claims.

The invention claimed is:

I. In a domestic oven structure of the type in which integral fume and odor removal means includes a plenum chamber receiving heated air from the oven interior and a partition defining one wall of the plenum chamber with a blower mounted on the face of said partition remote from the plenum chamber and having its intake communicating in sealed relationship through the partition and with said plenum chamber to thereby draw heated air therefrom and in which the oven structure is further provided with a control housing overlying but spaced from said remote face of the partition, the improvement comprising: a removable plate forming said partition, said plate having an aperture therethrough below said control housing, a sensing element for a temperature responsive limit control positioned at the base of said control housing and extending into closely spaced relation to and registering with said plate aperture, whereby while the turns removal blower is operating unheated air is drawn from the exterior of the oven plenum chamber around said temperature sensing element and through said plate aperture, and when said blower ceases operation heated air in said plenum chamber moves by convection through said plate aperture to provide a rapid temperature rise of said limit control sensing element.

2. In a domestic oven structure of the type in which integral fume and odor removal means includes a plenum chamber receiving heated air from the oven interior and a partition defining one wall of the plenum chamber with a blower mounted exteriorly of the plenum chamber and having its intake communicating in sealed relationship through the partition and with said plenum chamber to thereby draw heated air therefrom and in which the oven structure is further provided'vvith a control housing overlying but spaced from said remote fiace of the partition, the improvement comprising: a deck plate forming said partition, said plate having an aperture therethrough below said control housing, a sensing element for a temperature responsive limit control positioned at the base of said control housing and extending into closely spaced relation to and registering with said plate aperture, whereby while the fume removal blower is operating unheated air is drawn from the exterior or the oven plenum chamber around said temperature sen-sing element and through said plate aperture, and when said blower ceases operation heated air in said plenum chamber moves by convection through said plate aperture to provide a rapid temperature rise of said limit control sensing element.

3. In a domestic oven structure of the type in which integral fume and odor removal means includes a plenum chamber receiving heated air from the oven interior and a partition defining one wall of the plenum chamber with a blower mounted exteriorly of the plenum chamber and having its intake communicating in sealed relationship through the partition and with said plenum chamber to thereby dravv heated air therefrom, the improvement comprising: a deck plate forming said partition, said plate having an aperture thereth-rough, a sensing element for a temperature responsive limit control positioned exteriorly of said plenum chamber and extending into closely spaced relation to and registering with said plate aperture, Whereby While the fume removal blower is operating unheated air is drawn from the exterior of the oven plenum chamber around said temperature sensing element and through said plate aperture, and when said blower ceases operation heated air in said plenum chamber moves by convection through said plate aperture to provide a rapid temperature rise of said limit control sensing element.

4. In a domestic oven structure of the type in which integral fume and odor removal means includes a plenum chamber receiving heated air from the oven interior and a partition defining one wall of the plenum chamber with an air moving means in sealed communication with said plenum chamber operative to establish a negative pressure in the plenum chamber and in which the oven structure is further provided with a control housing overlying but spaced from the face of the partition remote from the plenum chamber, the improvement com prising: an aperture formed in said partition adjacent said control housing, a sensing element for a temperature responsive limit control carried by said control housing and extending into closely spaced relation to and registering with said partition aperture, whereby while the air moving means is operating unheated air is drawn from the exterior of the oven plenum chamber around said temperature sensing element and through said partition aperture, and when said air moving means ceases operation heated air in said plenum chamber moves through said partition aperture to provide a rapid temperature rise or said limit control sensing element.

References Cited by the Examiner UNITED STATES PATENTS 5/1958 Weaver et a1. 98-115 8/ 1962 Kimberley 126-21 

1. IN A DOMESTIC OVEN STRUCTURE OF THE TYPE IN WHICH INTEGRAL FUME AND ODOR REMOVAL MEANS INCLUDES A PLENUM CHAMBER RECEIVING HEATED AIR FROM THE OVEN INTERIOR AND A PARTITION DEFINING ONE WALL OF THE PLENUM CHAMBER WITH A BLOWER MOUNTED ON THE FACE OF SAID PARTITION REMOTE FROM THE PLENUM CHAMBER AND HAVING ITS INTAKE COMMUNICATING IN SEALED RELATIONSHIP THROUGH THE PARTITION AND WITH SAID PLENUM CHAMBER TO THEREBY DRAW HEATED AIR THEREFROM AND IN WHICH THE OVEN STRUCTURE IS FURTHER PROVIDED WITH A CONTROL HOUSING OVERLYING BUT SPACED FROM SAID REMOTE FACE OF THE PARTITION, THE IMPROVEMENT COMPRISING: A REMOVABLE PLATE FORMING SAID PARTITION, SAID PLATE HAVING AN APERTURE THERETHROUGH BELOW SAID CONTROL HOUSING, A SENSING ELEMENT FOR A TEMPERATURE RESPONSIVE LIMIT CONTROL POSITIONED AT THE BASE OF SAID CONTROL HOUSING AND EXTENDING INTO CLOSELY SPACED RELATION TO AND REGISTERING WITH SAID PLATE APERTURE, WHEREBY WHILE THE FUME REMOVAL BLOWER IS OPERATING UNHEATED AIR IS DRAWN FROM THE EXTERIOR OF THE OVEN PLENUM CHAMBER AROUND SAID TEMPERATURE SENSING ELEMENT AND THROUGH SAID PLATE APERTURE, AND WHEN SAID BLOWER CEASES OPERATION HEATED AIR IN SAID PLENUM CHAMBER MOVES BY CONVECTION THROUGH SAID PLATE APERTURE TO PROVIDE A RAPID TEMPERATURE RISE OF SAID LIMIT CONTROL SENSING ELEMENT. 